Inorganic per-salts have been known for a long time as bleaching additives in detergents. However, since they only display their optimum bleaching power at temperatures above 60.degree. C., a number of organic compounds which react with hydrogen peroxide during the washing process to release a peroxycarboxylic acid, which already has a bleaching action at 40-60.degree. C., have been described for activation of these per-salts. A review of numerous known perborate activators, such as N-acyl compounds (tetraacetylethylenediamine, tetraacetylmethylenediamine or tetraacetylglycoluril) or activated esters (pentaacetylglucose, sodium acetoxybenzenesulfonate or sodium benzoyloxybenzenesulfonate) is given, for example, in U.S. Pat. No. 4,248,928.
In addition, a number of organic peroxycarboxylic acids have recently been described as bleaching systems for detergents. As well as peroxycarboxylic acids which are already commercially available, such as dodecanedipercarboxylic acid (EP 127,782) and monoperoxyphthalic acid (EP 27,693), persuccinic acid (DE 3,438,529), perglutaric acid (DE 3,539,036) and sulfoperbenzoic acid (EP 124,969) are described. The problem with these peroxycarboxylic acids is, however, their low storage stability, which in some cases is only guaranteed by particular physical or chemical stabilization. The preparation of magnesium salts (EP 105,689) or an addition of phosphane oxide/sodium sulfate (DE 3,320,497) has proved to be particularly appropriate here. According to EP 170,386, organic peroxycarboxylic acids are also stabilized by an additional amide group in the molecule. Examples of these are N-decanoyl-6-aminoperoxycaproic acid or 3-(N-nonyl-carbamoyl)-perpropionic acid. The storage stability of these compounds can be additionally increased by conversion into the magnesium salt and by addition of borates (U.S. Pat. No. 4,686,063). However, the free peroxycarboxylic acids described to date already exhibit a clear decrease in active oxygen under relatively mild storage conditions. As our own experiments show, this is also the case with the imidopercarboxylic acids already described in J. Chem. Soc. 1962, 3821 and Chem. Ind. 1961, 469. There thus continues to be a great interest in storage-stable organic peroxycarboxylic acids having a high bleaching efficiency which are conveniently accessible in a simple and reliable manner.